Lens grinding machine



Nov. 6, 1934. w. c. PRIEST LENS GRINDING MACHINE Filed Dec. 3l, 1930 2 Sheets-Sheet l W P/P/ST INVENTOR.

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A TTORNEY Nov. 6, 1934. w. c. PRIEST LENS GRINDING MACHINE Filed Dec. 5l, 1930 2 Sheets-Sheet 2 TIE INVENTOR ATTORNEY Patented Nov. 6, 1934 UNITED STATES PATENT OFFICE LENS GRINDING MACHINE William Charles Priest, Davenport, IowaA Applica/tion December 31, 1930, Serial 505,728

Claims. (Cl. 51-7-1241) The present invention pertains to mechanism for the grinding of lenses and among the objects thereof are to provide an improved machine for the purpose stated; to provide a machine of the' lens `supporting block oscillates in a plane at right angles to the plane of rotation of the lens supporting block; to provide a structure of the character indicated in which the grinding cap is mounted to adjust itself so `thatfits axis coincides with a radius of the block; and such further objects, advantages and capabilities as will hereafter appear and asare inherent in the construction disclosed herein. My invention further resides in the combination, construction andarrangement of parts illustrated in the accompanying drawings and, while I have shown therein "what is now considered the preferred embodiment of this invention, I desire the same to be understood as illustrative only and not to be interpreted vin `a limiting sense.

In the drawings annexed hereto and forming a part hereof,

Fig. 1 is a snide elevation of a construction embodying my present invention;

Fig. 2 is a front elevation of this structure taken from the right in Fig. 1; H Y Fig. 3 is a plan view looking `down upon the structureof Fig. 2; l

Fig.` 4fis a section through the lenssupporting blocksubstantially on the plane indicated by line 4 4, Fig. 5; 401 Fig. 5 is a transverse 'section substantially along the plane indicated by the line 5 5, of Fig. 4;

Reference will now be made in greater detail to the annexed drawings in whichlike reference numerals designate like parts in allof'the figures. In these drawings, a pair of brackets 1 and 2 are shown as supported upon frame members 3 and 4, while a base 5 is supported upon any suitable bench, table or the like. The bracket 2 `preferably has a pair of arms 6 and 7 to hold the shaft 8 in alignment and to permit vertical motion thereof with respect to the remainder of the structure.

Bearings 9 and 10 are carried by arms 11 forming a part of the bracket 1. In these bearings are mounted shafts 12 and 13 which preferably are separated from the bearings 9 and 10 by suitable bushings, such as bronze bushings. On the'inner ends of these two shafts are gears 14 and r15 which mesh with a gear 16 having an 60=A elongated hub which extends into a bearing17 on the bracket 2. This elongated hub tends to prevent rocking ofthe gear 16 during operation of the machine. `As indicated at 18, the shaft 8. is squared and passes through a similarly shaped f opening in the gear 16. This therefore gives driving connection between these two elements but" permits the shaft to slide longitudinally through the gear and its hub. This is necessary, or at least desirable, in order to get the grinding i cap 19 away from the lens supporting block. In axial alignment with the shaft S isa projection whichfits into an opening in the stem of the grinding cap 19 and a collar 20 has a pin on the lower face thereof which engages a cooperating m, opening in the stem of this cap. This gives driv ing connection between these two elements and permits the driving cap to adjust itself to the lens supporting block so that the axis of the cap` will coincide with aradius'ofthe block. A bear- 8O v ing 21 is carried by the lower arm 7 of the bracket 2 and furnishes support for the lower cylindrical portion of theshaft 8.

Arms 22 rise from the base 5 and'have'bearings 23 for the axles 24. These Aaxles are carried by a 85 ring 25 which is adapted 'to be oscillated in'a substantially vertical direction upon these axles. The means for causing this oscillation includes a sleeve 26 forming a part of ring 25er non-rotatably connected thereto, a link 28 and a crank 29, 90 the latterbeing secured tothe shaft 13. A shaft 2'7 passes through ring 25 and collar` 26. Apair of pivots 30 and 31 permit the necessary pivotal motion between the parts 26 and 28, occasioned by the rotation of shaft 13 and crank 29 and the 95 oscillation of `ring 25 upon axle 24. Pivotal action at the upper end of link 28 i's also necessary and this is provided for in pivot 32 and crank pin 33 which is illustrated as being a bolt extending through the connector 34, a spacer 35 and the crank 29. `Preferably the crank 29 is slotted for adjustment of the crank pin 33 toward and away from the axis of shaft 13 and it is therefore desirable to have the spacer 35 in the form of a nut which can cooperate in holding the crank pin 33 in properly adjusted position.

On the shaft 12 is a belt pulley 36 over which passes a drive belt 37. This also passes over the belt pulley 38 securedto the shaft 39. A pulley A0 is carried. by the lever 41`pivoted on the bracket 110 42 which is secured in position in any desired manner. This is illustrated as being mounted upon the lower edge of frame member 4. A spring 42 is illustrated as secured to the frame member 3 and to lever 41. This pulls the pulley 40 against the belt 37 and keeps it tight at all times. This is quite essential in view of the fact that the ring 25, carrying the block 43, rocks upon the aXis 24. This rocking is caused by the crank 29 and link 28, above described. This operation will be given more in detail hereinafter. As the ring 25 oscillates, the belt wheel 88 rises and falls and has a tendency to cause the belt 37 to have slack and to be tightened up. The pulley 40, lever 4l and spring 42 cause all of the slack to be taken up so that the belt is substantially uniformly tight.

The lens blank supporting block 43 is shown as a hollow, substantially spherical shell having a series of spokes 44 connected thereto and to an elongated hub 45 which nts tightly on a shaft 46, being keyed or pinned thereto, if desired, but I consider it preferable to have the shaft and hub fit so tightly that no securing means is necessary. Openings 47 are provided on opposite sides of the block 43 for the passage of the shaft 46. Elevated patches 48. are provided upon the surface of the lens supporting block for the purpose of receiving the lens blanks which are to be ground. These areas 48 are not illustrated in any of the figures except 4 and 5 but it is to be understood that they substantially cover the surface of the block, whether shown or not. A tank or trough 49 which is preferably partly spherical in form may be provided with legs 50 by means of which it may be supported from the'base 5. The purpose of this trough is to contain the liquid suspension of grinding powder which is customarily used in such operations. It is preferable to have the trough 49 removably mounted on the base 5 so that if it is desired to pick up the same and empty it, this may be done. As is evident from the drawings, the block 43 dips into the trough 49 a considerable distance and, therefore, quite a number of the lens blanks are immersed in the suspension of grinding'powder.

The shaft 46 is shown as having a conical depression 51 in one end thereof and a collar 52 surrounding this end and secured thereto. This collar is shown as provided with a plurality of holes 53 for the reception of pins projecting from the face of a drive collar 54 on the end of shaft 39; Itfwill therefore be apparent that when the conical opening 511 is placed inr registry with the conical point on the inner end of the shaft 39v and the openings 53 are lined up with the pins in the collar 54, shaft 46 and block 43 may be shoved tothe left, as viewed in Fig. 2, and the shafts 39 and 46 will then be in driving relation. The inner end of shaft 27 has a conical depression therein for the reception of the conical projection 55 on the cap 56, shown at the right of Fig. 5. This cap carries driving pins 57, which correspond to the'pins cooperating with the openings 53 and iit into similar openings in the collar 58 rigidly secured to the shaft 27. In order to permit the parts to be assembled, there is a space 56a between theA end of cap 56 and the shaft 46 which permits the cap to be shoved to the left, as seen in Fig. 5, after the set screw 59 has been loosened. In order that this cap may have a driving connection with the shaft 46, the latter is iiattened upon one side for engagement by the set screw 59. When the parts have been properly lined up, the collar 56 is moved to the right until projection 55 engages the conical depression inl collar 58 and the driving pins 57 engage in the depressions in this collar. When a proper driving connection has been made, the set screw 59 is turned in until it grips the shaft 46 sufficiently to prevent movement of the cap with relation to the shaft.

Operation In getting ready to use this device, the lens blanks are mounted upon the fiat faces 48 and are secured in place thereon by any suitable wax, the same being well known to the trade. The block is then applied within the ring 25 as above described, and secured in place by shoving the cap 56 outwardly so that the pins 57 and conical projection 55 engage in their cooperating depressions. The set screw 59 is then turned in until the parts are secured in rigid relation. The grinding cap 19 is then lowered until it rests upon the lens blanks mounted on the block and the machine is set into operation. Any suitable method of applying driving power is used but I prefer to apply such power by means of a bevel gear similar to gear 16, the same being mounted above the gears 14 and l5 and meshing with the same. The hub of this gear should be hollow to permit the shaft 8 to extend up through the same when the grinding cap 19 is raised. A belt pulley may be mounted upon and secured to the hub of this gear and power will then be applied to both the gears 14 and 15 when the belt is driven. Inasmuch as the driving means is not considered a part of the present invention and any other suitable means might be used, such driving means has not been illustrated. When the gears 14 and l5 are rotated, power is applied to shafts 8, 12 and 13 and is transmitted from these to the grinding cap 19, the shaft39 and the link 28. Rotation of the shaft 8 rotates the grinding cap 19 in a substantially horizontal plane while rotation of the shaft 39 rotates the block in a direction perpendicular to that of the grinding cap. Reciprocation of the link 28 causes oscillation of the ring 25 about the axles 24 and corresponding oscillation of the block in a direction perpendicular to the direction of motion of the cap 19 and rotation of the block with the shafts 39 and 27. We thus get our grinding action in three directions atright angles to each other which tends to reduce to a minimum the amount of scratching and scarring of the lenses during the grinding operation. Withy this machine, the number of spoiled lenses is reduced to a minimum. As the belt pulley 38 lowers, with the oscillation of the ring 25, the belt 37 is tightened and the spring 42 is extended. When the link 28 is lowered by the crank 29, the belt pulley 38 is raised and the belt 37 tends to become slack. However, spring 42 pulls up on arm 41 and causes the pulley 40 to take up all of the slack of the belt. There is therefore a driving torque applied constantly to the belt pulley 38 and shaft 46 to cause rotation of the block 43.

A rigid arm might be substituted for the pivoted lever 41, said arm terminating substantially midway between the two stretches of the belt 37 and having an arm pivoted on the end thereof, said pivoted arm having a pulley upon each end corresponding to the pulley 40 so that both stretches of the belt 37 would have pressure applied thereto to cause tightening of the belt. This pivoted arm might have a crank arm secured to or integral therewith to which the spring might be attached for causing rotation of said pivoted arm during the take-up action. Such a construction is contemplated as coming within the scope of the appended claims.

It is of course understood that the specific description of structure set forth above may be departed from without departing from the spirit of my invention as set forth in this specication and the appended claims.

Having now described my invention, I claim:

1. A lens grinding machine comprising a support, a ring pivoted thereon to rock with relation to said support, a shaft rotatably carried by said ring, the same being diametrically mounted therein, means for rocking said ring, means for rotating said shaft, a lens-blank support carried by said shaft and partaking of said motions, a grinding lap carried in proximity to said blank support and cooperating therewith in the grinding of lenses, and means for causing rotary movement of said lap.

2. A lens grinding machine comprising in combination a support, trunnions connected to said support, a ring carried by said trunnions and Capable of oscillating thereon with relation to the support, a shaft rotatablyy carried by said ring and extending across the same, a lens-carrying block carried by the shaft and rotated thereby within the ring, when the shaft is rotated, means for rotating said shaft, means for oscillating the ring on the trunnions, and a grinding lap to cooperate with the block, the axis of the lap normally intersecting the axes of the ring and shaft at their point of intersection.

3. A structure as defined by claim 2 in which the means for oscillating the ring comprises a rotary shaft and a linkage connection connecting the ring eccentrically to the shaft.

4. A structure of the character indicated comprising a support, a ring mounted in said suplport to oscillate upon a substantially horizontal axis, an axle extending substantially diametrically of said ring and mounted therein for rotation, a lens carrying block secured to said axle and rotating therewith, a grinding lap mounted adjacent said block and rotating 'with relation thereto to cooperate therewith in the grinding of lenses, means for rotating said lap, means connected therewith for rotating said axle, and further means connected therewith for oscillat ing said ring.

5. A structure as dened by claim 4 in which said lap is mounted to be moved away from the block to permit removal of the latter and substitution of another.

WILLIAM C. PRIEST. 

